Conventionally, high velocity grenades rely on a mechanical impact fuze located in the front of the grenade. The mechanical impact fuze is a complex device that uses environmental parameters associated with gun launch (e.g., setback and spin) to arm. Upon impact with a target the nose of the mechanical impact fuze is crushed. This action projects a stabber into an explosive charge located at the base of the mechanical impact fuze. A charge detonates and launches a metal projectile towards a main charge, which then detonates upon impact. This action collapses a metal shaped charge liner, which is projected forward through the mechanical impact fuze and into the target. At the same time the main charge fragments the body of the grenade and throws those fragments outward.
There are several limitations with conventional systems. The mechanical impact fuze is a complex device that is prone to failure. It has been known to arm and detonate early, posing a hazard to the gunner. These failures have primarily been attributed to errors made during manufacturing. The mechanical impact fuze may also fail to fire if the weapon impacts at an oblique angle or hits soft material such as snow. This situation poses an unexploded ordnance hazard to operators and bystanders. In addition, the presence of the mechanical impact fuze in front of the shaped charge inhibits the ability of the weapon to penetrate armor. Before the shaped charge can penetrate the target it must first go through the steel and aluminum components of the mechanical impact fuze. Further, the rear of the fragmenting grenade body has a tendency to come off as a single piece and fly straight back, which is a hazard to the gunner. Finally the device does not meet Department of Defense (DOD) “Insensitive Munitions” requirements, which are standards designed to reduce of risk of injury to personnel as a result of accidents such as dropped items or a fire.